add documentation

README.md

@@ -5,3 +5,70 @@ Dekalee/NightlyTaskBundle
 [![Latest Stable Version](https://poser.pugx.org/dekalee/nightly-task-bundle/v/stable)](https://packagist.org/packages/dekalee/nightly-task-bundle)
 [![Total Downloads](https://poser.pugx.org/dekalee/nightly-task-bundle/downloads)](https://packagist.org/packages/dekalee/nightly-task-bundle)
 [![License](https://poser.pugx.org/dekalee/nightly-task-bundle/license)](https://packagist.org/packages/dekalee/nightly-task-bundle)
+
+This bundle will launch all the configured nightly task.
+
+Installation
+------------
+
+Use composer to install the bundle
+
+```bash
+    $ composer require dekalee/nightly-task-bundle
+```
+
+If you are not using symfony4 you should activate the bundle in your
+`AppKernel.php` file.
+
+```php
+    new Dekalee\NightlyTaskBundle\DekaleeNightlyTaskBundle(),
+```
+
+Usage
+-----
+
+### List commands
+
+To list all the commands register as nightly task command run
+
+```bash
+    $ ./bin/console dekalee:nightly:list
+```
+
+### Launch commands
+
+To launch the nigthly tasks, run the command :
+
+```bash
+    $ ./bin/console dekalee:nightly:tasks
+```
+
+### Define a command as nightly tasks
+
+#### With an interface
+
+To define a command as a nigthly task, it should implement the
+`Dekalee\NightlyTaskBundle\Command\NightlyCommandInterface` interface.
+
+This interface will expose two methods:
+
+ - `getPriority` will define the order in which the command should be run.
+ Higher priority wins.
+ - `isEssential` will determine if the nighty task command should fail
+ if this particular command fails.
+
+#### With a tag
+
+It is also possible to transform a command in a nightly task by tagging
+the service directly.
+
+```yaml
+   tags:
+       - { name: console.command }
+       - { name: dekalee_nightly.task.strategy, priority: 100 }
+```
+
+Your service should be defined as a command and then defined as a nightly
+task with a priority.
+
+It is not possible to make those kind of command essential.